This invention relates to fluoroelastomeric compositions based on vinylidene fluoride, having a high adhesion to metals in the vulcanized state, and characterized in that they contain a minor amount of chlorotrifluoroethylene which is present as a comonomer of an elastomeric copolymer of vinylidene fluoride.
The fluoroelastomers with a high fluorine content have generally found a wider and wider utilization in the fields in which a high chemical stability and an excellent resistance to temperatures of 260.degree. C. for continual use are required.
In a few of these utilizations, for example in the field of the sealing on rotary shafts accomplished by means of oil retaining rings, besides the characteristics which are typical of these elements, which are broadly described in literature [for example in Rubb. Ch. Tec. Vol. 55, page 908 (1982)], it is absolutely necessary that between the elastomer, constituting the sealing element of the gasket, and the metal insert, a perfect adhesion characterized by high adhesion coefficient values should be attained.
Therefore, there is the need for some manufactured articles vulcanized from fluoroelastomers to reach a satisfactory vulcanization rate and processing safety, a high metal-to-rubber adhesion which, by remaining unaltered even at high temperatures, renders the vulcanized articles suitable for being used also under the most severe working conditions.